Experimental Setup – Simultaneous K+/K- beams
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Measurement of the Cabbibo-Kobayashi-Maskawa Quark-Mixing matrix element Vus from 2003 data from NA48/2 experiment at CERN Anne Dabrowski (work done in collaboration with advisor Prof. Mayda Velasco, research assistant Michal Szleper and the NA48/2 Collaboration at CERN) Northwestern University, Evanston, Il Experimental Setup – Simultaneous K+/K- beams 1cm 50 100 DFDF Quadrupole 2 nd Quadruplet ACHROMAT FRONT-END ACHROMAT 10 cm 200 250 m vacuum tank He tank + spectrometer magnet B+ K + K - K + K - focusing beams 114m decay volume beams coincide within <1mm FDFD not to scale TAX 17 TAX 18 NA48/2 Detector •Main detector components ● Magnet spectrometer ➢ Two drift chambers before and two after spectrometer magnet ➢ Momentum resolution < 1% for 20 GeV/c momentum ● Anti-counters ● Liquid Krypton Calorimeter ● Hadron Calorimeter ● Muon Veto system ● Beams K ± Data sample from a Data sample from a special low intensity special low intensity run run 2003 2003 Data Sample Data Sample : : • 8 h K 8 h K + /K /K - with min bias trigger with min bias trigger ... no cut at trigger level on Dalitz ... no cut at trigger level on Dalitz plot, & plot, & ε ε trig trig ~ 99.8% ~ 99.8% K K e3 e3 Br measurement: Br measurement: • Normalize K Normalize K e3 e3 events to events to π π ± π π 0 events events Br( Br( π π ± π π 0 ) = 0.2113 ) = 0.2113 ± ± 0.0014 0.0014 • Selected Events Selected Events : : • K K e3 e3 + ..... 59k K ..... 59k K e3 e3 - ..... 33k ..... 33k • π π ± π π 0 ..... 468k ..... 468k π π ± π π 0 ..... ..... 260k 260k Data/MC Comparison for Br(K Br(K e3 e3 ) ) measurement Data/MC Mom. of Mom. of Track Track pipi0 pipi0 Energy Energy π π 0 Data/MC Mom. of Mom. of Track Track Energy Energy π π 0 K K e3 e3 Data/MC Data/MC New Preliminary NA48/2 Br(K New Preliminary NA48/2 Br(K e3 e3 ) ) Br(K Br(K e3 e3 ) = (5.14 ) = (5.14 ± ± 0.02 0.02 stat stat ± ± 0.06 0.06 syst syst )% )% Systematics: σ sys variation of reconstruction cuts ±0.038% Br(K→ π ± π 0 ) ±0.034% Radiative events ±0.006% Trigger efficiency ±0.004% MC statistics ±0.022% Total Systematics ±0.056% Statistical uncertainty ±0.017% V V us us from from K K e3 e3 Inputs into extracting Vus from Ke3 CKM matrix – Unitary Problem? • Unitarity of CKM matrix requires: Unitarity of CKM matrix requires: |V |V ud ud | | 2 2 +|V +|V us us | | 2 + |V + |V ub ub | | 2 = 1 = 1 • PDG 2004 data: PDG 2004 data: |V |V ud ud | = 0.9738 ± 0.0005 - well measured | = 0.9738 ± 0.0005 - well measured |V |V ub ub | = (3.67 ± 0.47).10 | = (3.67 ± 0.47).10 -3 -3 - ( |Vub| - ( |Vub| 2 ≈ 10 ≈ 10 -5 -5 negligible) negligible) • SM prediction SM prediction |V |V us us | = 0.2274 ± 0.0021 | = 0.2274 ± 0.0021 • Experimental value (begining 2003) Experimental value (begining 2003) |V |V us us | = 0.2200 ± 0.0026 | = 0.2200 ± 0.0026 |V |V us us | | = 0.0074 ± 0.0033 ~2.2 discrepancy = 0.0074 ± 0.0033 ~2.2 discrepancy 1 % Measurement needed 1 % Measurement needed (limited by theory) (limited by theory) V us x f + (0) Patera New Determinations of Vus • Similar Analysis, Normalize K m3 to π ± π 0 – Particle ID … 2 Methods for muon ID 1. Using the Muon Veto for Muon ID (global 99.92% efficient) 2. Using the Electromagnetic and Hadronic calorimeters for 1-MIP signal (max 98.% efficient, but momentum dependent) – Number of events: • μ + π 0 ν (μ - π 0 ν ) 60 k (33 k) – Statistical error comparable to K e3 Status of V Status of V us us from from K K 3 3 data data Muon ID efficiency using muons Muon ID efficiency using muons from from K K ± → → μ μ ± ν ν Radiative correction in Measurement of Br(Ke3) Ginsberg Implementation OK in MC generated events – see paper (Ginsberg Phys Rev vol 162 Num 5 25 October 1967) Data/MC, radiative corrections on Data/MC, radiative corrections off Data/MC Comparison for Br( K Data/MC Comparison for Br( K m3 m3 ) measurement Data/MC looks good! Br(K Data/MC looks good! Br(K 3 ) available ) available soon!! soon!! Mom. of Track Mom. of Track Energy Energy π π 0
description
Measurement of the Cabbibo-Kobayashi-Maskawa Quark-Mixing matrix element Vus from 2003 data from NA48/2 experiment at CERN Anne Dabrowski (work done in collaboration with advisor Prof. Mayda Velasco, research assistant Michal Szleper and the NA48/2 Collaboration at CERN) - PowerPoint PPT Presentation
Transcript of Experimental Setup – Simultaneous K+/K- beams
Measurement of the Cabbibo-Kobayashi-Maskawa Quark-Mixing matrix element Vus from 2003 data from NA48/2 experiment at CERN
Anne Dabrowski
(work done in collaboration with advisor Prof. Mayda Velasco, research assistant Michal Szleper and the NA48/2 Collaboration at CERN)
Northwestern University, Evanston, Il
Measurement of the Cabbibo-Kobayashi-Maskawa Quark-Mixing matrix element Vus from 2003 data from NA48/2 experiment at CERN
Anne Dabrowski
(work done in collaboration with advisor Prof. Mayda Velasco, research assistant Michal Szleper and the NA48/2 Collaboration at CERN)
Northwestern University, Evanston, Il
Experimental Setup – Simultaneous K+/K- beams
1cm
50 100
DFDFQuadrupole 2nd
Quadruplet ACHROMATFRONT-END ACHROMAT
10 cm
200 250 m
vacuum tank
He tank+ spectrometer
magnetB+
K+
K-
K+
K-
focusing beams
114m decay volumebeams coincide within <1mm
FDFD
not to scale
TAX 17 TAX 18
NA48/2 Detector
•Main detector components● Magnet spectrometer
➢Two drift chambers before and two after spectrometer magnet
➢Momentum resolution < 1% for 20 GeV/c momentum
● Anti-counters ● Liquid Krypton Calorimeter ● Hadron Calorimeter● Muon Veto system● Beams K±
Data sample from a Data sample from a special low intensity runspecial low intensity run 20032003
Data SampleData Sample::• 8 h K8 h K++/K/K-- with min bias trigger with min bias trigger
... no cut at trigger level on Dalitz ... no cut at trigger level on Dalitz plot, & plot, & εεtrigtrig ~ 99.8% ~ 99.8%
KKe3e3 Br measurement: Br measurement:
• Normalize KNormalize Ke3e3 events to events to π π ±±ππ00 events events
Br(Br(π π ±±ππ00) = 0.2113) = 0.2113±±0.00140.0014• Selected EventsSelected Events::
• KKe3e3++ ..... 59k K ..... 59k Ke3e3
-- ..... 33k ..... 33k• π π ±±ππ00 ..... 468k ..... 468k π π ±±ππ00 ..... 260k ..... 260k
Data/MC Comparison for Br(KBr(Ke3e3) )
measurement
Data/MC
Mom. of Mom. of TrackTrack
pipi0 pipi0
Energy Energy ππ00
Data/MC
Mom. of TrackMom. of Track Energy Energy ππ00
KKe3e3
Data/MC Data/MC
New Preliminary NA48/2 Br(KNew Preliminary NA48/2 Br(Ke3e3))
Br(KBr(Ke3e3) = (5.14 ) = (5.14 ±± 0.02 0.02 statstat ± ± 0.06 0.06 systsyst)%)%
Systematics: σsys
variation of reconstruction cuts ±0.038%
Br(K→ π ±π0) ±0.034%
Radiative events ±0.006%
Trigger efficiency ±0.004%
MC statistics ±0.022%
Total Systematics ±0.056%
Statistical uncertainty ±0.017%
VVusus fromfrom K Ke3e3
Inputs into extracting Vus from Ke3CKM matrix – Unitary Problem?
• Unitarity of CKM matrix requires:Unitarity of CKM matrix requires:
|V|Vudud||2 2 +|V+|Vusus||22+ |V+ |Vubub||22 = 1 = 1• PDG 2004 data:PDG 2004 data:
|V|Vudud| = 0.9738 ± 0.0005 - well measured| = 0.9738 ± 0.0005 - well measured
|V|Vubub| = (3.67 ± 0.47).10| = (3.67 ± 0.47).10-3 -3 - ( |Vub|- ( |Vub|22 ≈ 10 ≈ 10-5-5 negligible) negligible)• SM prediction SM prediction
|V|Vusus| = 0.2274 ± 0.0021| = 0.2274 ± 0.0021• Experimental value (begining 2003)Experimental value (begining 2003)
|V|Vusus| = 0.2200 ± 0.0026 | = 0.2200 ± 0.0026 |V|Vusus|| = 0.0074 ± 0.0033 ~2.2 discrepancy= 0.0074 ± 0.0033 ~2.2 discrepancy
1 % Measurement needed 1 % Measurement needed (limited by theory)(limited by theory)
Vu
s x
f+(0
)
Patera New Determinations of Vus
• Similar Analysis, Normalize Km3 to π ±π0
– Particle ID … 2 Methods for muon ID1. Using the Muon Veto for
Muon ID (global 99.92% efficient)
2. Using the Electromagnetic and Hadronic calorimeters for 1-MIP signal (max 98.% efficient, but momentum dependent)
– Number of events:• μ+π0ν (μ-π0ν ) 60 k (33 k) –
Statistical error comparable to Ke3
Status of VStatus of Vusus from from K K33 datadata
Muon ID efficiency using muonsMuon ID efficiency using muons fromfrom K K±±→→μμ±±νν
Radiative correction in Measurement of Br(Ke3)
Ginsberg Implementation OK in MC generated events
– see paper (Ginsberg Phys Rev vol 162 Num 5 25 October 1967)
Data/MC, radiative corrections on
Data/MC, radiative corrections off
Data/MC Comparison for Br( KData/MC Comparison for Br( Km3m3) measurement
Data/MC looks good! Br(KData/MC looks good! Br(K33) available soon!!) available soon!!
Mom. of TrackMom. of Track Energy Energy ππ00
